Complaint Review: The Trivia Pages

We had been contacted by a man named Denis Little from Trivia Pages.  He informed us that he does great advertising, we had agreed and he told us to rush him a copy of what we wanted our to look like. We did, we also paid over $500 for it.  We had never heard back from this Denis again.  I have left them many voicemails and called the cell phone number they had given us.  It never went through.  We are wanting to file a law suit against them, but we don't even know if there is an actual person to make the case against! My boss is not pleased with this.